1. Field of the Invention
This invention relates to a metallurgical plant comprising an enclosure and in said enclosure a metallurgical vessel, which is mounted to be tilted about a horizontal axis and is provided with a cover that is adapted to be lifted and is horizontally pivotally movable from the vessel so that the latter can be charged by means of a charging box, which is suspended by means of ropes from a charging crane that is disposed outside the enclosure. The enclosure is formed in a side wall with a charging opening, which is adapted to be closed. The charging box is adapted to enter the enclosure through said charging opening. The enclosure has a top wall in which a top wall opening extends from and is open to the charging opening. Said top wall opening is adapted to be closed and when open permits the ropes of the charging crane to move in said top opening at least as far as to the vertical center line of the vessel. A space for receiving the charging box while the cover of the vessel is being opened and closed is provided between the vessel and that side wall which is formed with the charging opening.
2. Description of the Prior Art
It is known (Grubert, K.; Haering, H. U.; Marchand, D.; Muth, S.: Einsatz enger Elektroofen-Einhausungen zur Abgaserfassung und L/a/ rmminderung, Stahl und Eisen 104 (1984), No. 5, pages 235 to 239) that the pollution caused by an evolution of flue gas during the charging of a metallurgical vessel, particularly an electric furnace, can be limited in that the electric furnace is surrounded by an enclosure, which provides between the furnace and a side wall formed with a charging opening a space which is adapted to receive a charging box, which by means of a charging crane disposed outside the enclosure can be moved through the charging opening in said side wall to a waiting position. The enclosure can then substantially be closed and thereafter the cover of the furnace can be lifted and can be horizontally pivotally moved away from the furnace vessel so that the latter can be charged from the charging box. In such plants the flue gases being evolved can be sucked inside the enclosure and the charging opening in the side wall of the enclosure needs to be opened only when the furnace is closed by its cover. Because the charging box when in waiting position will be disposed in front of the slag door of the furnace, on the side which is opposite to the tap hole, the slag door is not accessible from the outside of the enclosure but an access to the furnace is possible only from a walk-in access chamber, which is disposed within the enclosure and has swing doors opening toward the furnace. The provision of that chamber increases the structural expenditure and renders the access to the furnace more difficult. Besides, when the charging box is suspended from a suspension tackle and the ropes of the charging crane are connected to the suspension tackle at points which are spaced a relatively large distance apart in the direction of the horizontal axis about which the electric furnace is tiltable, the top wall must be formed with a top wall opening which is open to and extends from the charging opening at least as far as to the vertical center line of the vessel. Said top wall opening serves to receive the ropes of the charging crane and must have a width which exceeds the distance between the crane ropes. As a result, there is a relatively large opening in the top wall of the enclosure when the charging box is in its waiting and charging positions, even though the top wall opening can be closed in part of its length.